Gas and air mixer.



No; 65!,779. Patented lune l2, I900. v G. R. CUTTRELL.

I GAS AND AIR MIXER.

(Application filed Aug. 25, 1899.)

2 Sheets-Shoat I.

(No Model.)

. WASHINGTON o c No. s5|,779. Patented lune l2, I900.

e. R. COTTBELL.

GAS AND AIR MIXER. (Application filed Aug. 25, 1899.)

Model-Y 2 SheetsShaet 2.

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. UNITED STATES PATENT Omen.

GEORGE R. COTTRELL, on NEW YORK, N. Y.

GAS AND AIR MIXER.

SPECIFICATION forming part of Letters Patent No. 651,779, dated June 12, 1900.

Application filed August 25, 1899. berial N0. 728,431- (No model.)

To all whom it may concern:

Be it known that I, GEORGE R. COTTRELL, a citizen of the United States, residing at New York, (Tottenville,) in the county of Rich-. mond and State of New York, have invented certain new and useful Improvements in Apparatus for Mixing Gas and Air; and I do hereby declare the following to be a full,clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to apparatus for mixing gas and air or gaseous fluids of diiferent gravities in the desired proportions under the same pressure or velocity, and thereby obtaining a perfectly-homogeneous mixture of the gas and air or other fluid at a moderate pressure for supplying the burners of'heating and cooking stoves and for other purposes.

In burning gas forheating and cooking purposes it is now a common practice to supply the current of gas to the burner-orifice at a comparatively-high velocity by means of an ind notion-burner of the Bunsen type, thereby drawing in or inducing the flow of a current of air at a low velocity for mingling with the gas to cause combustion thereof. The results attained in practice are'unsatisfactory and wasteful of gas for the reason that the currents of gas and air moving at different velocities and the fluids being of different gravities do not diffuse and perfectly commin gle,but,'on the-contrary, are held apart by a great law in nature, resulting in imperfect and only partial combustion of the carbon particles and a corresponding waste of gas. Gases of diiferent gravities, such as gas and air, must be united in positive measured proportions and also at the same velocity, so that when they are brought together the mixture will be perfect and homogeneous and in uniform proportions.

The object of my invention is to provide for overcoming the defects and objections in the gas and air mixing devices now in common use and to provide for mixing together currents-of gas and air under a uniform pressure and at the same velocity and in positivelylneasured proportions, so as to obtain a perfectly-homogeneous mixture in uniform proportions, and thereby secure perfect combus-" tion and greater economy in the use of gas for heating, cooking, and other purposes.

In my improved gas and air mixing apparatus the air-meter drum and the gas-meter drum are mounted upon the same shaft, and the pressure of gas is utilized for revolving the gas and air drums.

One of the special objects of my invention, therefore, is to reduce to the minimum the resistance to the revolution of the air and gas drums. This is accomplished by providing comparatively narrow or small inlet-openings to the screw measuring-compartments of the air and gas drums and comparatively wide or large outlet-openings for the same.

Another object of my invention is to provide increased and more efficient driving surfaces or shoulders in the spiral vanes of the gas-meter drum, so that such drum shall be more readily and efiectively propelled by the pressure of the gas which to be metered and mixed with the air.

The matter constituting my invention and improvements herein will be defined in the claims.

I will now particularly describe my improved apparatus by reference to the accom-' nal section of the casing, with the meterdrums in elevation and illustrating diagrammatically by dotted lines the screw measuring-compartments of gradually-increasing diameter from the inlet ends to the discharge ends thereof. Fig. 3 represents an end elevation. Fig. 4 represents a transverse section through the casing and one end of the gas-meter drum on line a; as, Fig. 2. Fig. 5 represents an end view of the gas-meter drum, showing by full lines the outlet-openings of the discharge end and indicating by dotted lines the inlet-openings of the receiving end, both intended to illustrate the unison of the sealing and discharging action of the drum. Fig. 6 represents a detached face view of one of the screw-vanes of the gas-drum. Figs. 7

and 8 represent, respectively, the receiving end and the discharging end of the air-meter compartments.

drum, illustratingdiagrammatically the comparative size'of the, inlet-openings and the discharge-openings of. the screw measuring- The outer cylinder or casing A, which contains the meter-drums, is preferably constructed of two half-cylinder sections provided with flanges a, which are secured togetlierby rivets or bolts in a well-known ma n-. ner. The cylinder A is supported on standards'or legs a. Within the cylinder A are mounted the two meter-drums B and upon the same shaft (1, which is journaled in suitable bearings in the gas and air supply pipes H and K at the opposite ends of the cylinder.

The drum B is styled the propellingdruin and is for measuring gas and driving or revolving the air-drum, and the drum 0 is styled the induction-drum and is for measuring and delivering air. The two drums are suitably spaced apart, so as to form a receiving-chamber D between their discharging ends for permitting the gas and air-as dis- 1 charged from the drums to intimately mixtogether and for receiving the water displaced by the screw measuring-compartments during the revolution of the drums. The drums and their shaft are preferably placed cen- V screw-vanes 1 2 3 4 5, placed equal distances apart and secured to the shaft 1. Each screw- -va.n e extends helically from the receiving or inlet end of the drum spirally a little more than one half-turn to the discharge end of the drum, forming screw measuring-compartments of gradually-increasingdiameters from the comparatively-narrow gas-inlets u at the receiving end tothe comparativelyavide outlets 'w'at thedischarge end of the drum, as shownin Figs. 7 and 8, so that the gas will be passed through said compartments and d isc'harge'd, with the least possible resistance. The screw measnring-compartments are not ofnincreasing diameter radially from shaft d, but from side to side in cross-section approximately on lines of chords through the drun1 The vanes at the receiving endsare Dmvided each with two ormore driving-shoulders b, which preferably extend radially fromnear theshaft to the shell ofthe drum, as shown in Figs. tand 6. These driving-shout ders. b are at the receiving or inlet end of the drum exterior to the screw measuring-cola partments and are styled exterior driving, -shoii1de1 s. Within the drums the screwvanes are also provided each with an interior driving-shoulder b',as shown in Fig. l. The

. measuringcompartments are formed by the adjacent helicalvan-es and extend from the shoulders before entering the compartments.

The driving shoulders or ofisets b taper from the periphery of the drum toward the shaft, as shown, and in each vane terminate a short distance from the shaft, so that when the vane is above the liquid-line the driving-shoulders shall not extend down into the liquid. smooth surface of thescre'w-vane is preferably near the center of the drum in order toavoid friction at that part which isa'lways be.- low the liquid-line, The speed at which the drum is to be revolved will be regulated by the number of driving-shoulders b, If a com- I paratively-high speed of rotation isrequired, the number of shoulders will be increased. If a. lower speed is required, the number of driving-shoulders will be decreased. The air inducing and measuring drum 0 is also constructed with a receiving-chamber f at the Y inlet end and; with five helical screw-vanes, forinin g between them five screw measuringcompartments having comparatively-narrow inlets so at the receiving end and comparatively-wide outlets y at the discharge end, as illustrated in Figs. 7 and 8, for reducing the i resistance and facilitating the revolution of the drum in displacing the air and sealing Eliquid The screw meastiring-compartments of the airdrum are preferably made with gradually-increasing diameters from side to fside from the narrow inlet-openings a: to the wide outlet-openingsy, as indicated by dotted Llines in Fig. 2, so as to facilitate the measur- Eing and displacement of the air and to overgcome resistance of the sealing liquid as the drum is revolved in the same. The vanes of ';;the air-drum extend helically, or nearly so, a Elittle; more than one half-turn from the rejceiving end to the discharging end of the drumand are securedto the shaft and outer shell. With this construction of the vanes and screw measuring-compartmentsthe inletlopenings of any one compartment will be sealed in the liquid just before'the outleto'pening of such compartment passes out of the'liquid seal, so that the air after entering the screw-compartment must always be propelled toward the discharge end thereof underthe same pressure as the gas is displaced, because the gas-pressure is out 01f from the sister gas-chamber, and they are both discharging by the filling up ofthe compartments with liquid under one pressure and Will algways benlov ed forward in uniform and positively-measuredquantities, a

The gas-meter drum and the air-meter drum being seen red to the same shaft, the air-drum will be revolved bythe pressure of gas on the drivingshoulders in the vanes of the gas? narrow inlets u. to theIwidei outle-ts w that drum, which latter being revolved will,

through the medium of the shaft common to both drums, drive or revolve the air-drum, thus measuring and mixing positive and uniform proportions of gas and air. The pressure of gas alone 011 the driving-shoulders in the vanes at the receiving end of the gas-drum drives or revolves both drums.

It is to be noted that the gaspressure is greatest and most effective at the receiving end of the gas-drum outside of the screw measuring compartments, since such compartments are of increasing or expanding crosssection toward the discharge end, thus providing for expansion, and consequently reduced pressure and easy discharge of the inflowing gas, so that it will not act effectively, except at the initiatory, to drive the drum.

The heads of the cylinder A are provided with openings, in one of which is secured theelbow-pipe H for admission of gas and in the other of which is secured the elbow-pipe K for admission of air. A gas-supply pipe It connects withthe elbow-pipe H. The elbowpipes H and K project up near the top of the receiving-chambers e and f to prevent outflow of the sealing liquid under excessive pressure of gas. ,The water or other sealing liquid is maintained at the level of the dotted line 2 z in Figs. 2 and 4, and suitable supply and overflow pipes (not here shown) will be provided in. practice.

A delivery-pipe L connects withthe cylinder 0, opening into the chamber D, for conducting the mixture of gas and air to the burner or other place of use. A water-gage n connects with one end of the cylinder for showing the height of the water in the same, and an index-dial m is secured to one end of the cylinder for indicating the number of feet of gas metered.

In constructing the gas and air mixing meter I am particular to so arrange the airdrum with relation to the gas-drum on the shaft that the outlets of the screw measuringcompartments of the air-drum shall not be opposite the outlets of the measuring-compartments of the gas-drum. Preferably the outlets of one drum are arranged to discharge midway between the outlets of the opposite drum. By this arrangement of the relative positions of the dischargingends of the drums I obtain a positive sealing action in both drums, so that the gas under pressure will never have a clear passage from the outlet of the gas-drum through any one of the measuring-compartments of the air-drum for the reason that the measuring-compartment of the air-dru m which is discharging air will be sealed at its inlet end and the measuringcompartment of the gas-drum which is discharging gas will at the same time be sealed at its inlet end.

charged in opposing currents one against the other, which would tend to retard rotation of the drums, but will be discharged into the chamber D at different points in the revolution of the drums, so as not to interfere one with the other. This prevents any dragging in the revolution of the drums. By my improved construction such defects and difficulties are entirely overcome.

Gas being admitted under pressure through the elbow-pipe H into the receiving-chamber e of the gas-drum bears upon the drivingshoulders I) of such screw-vanes as are above the surface .2 of the sealing liquid and causes revolution of the drum B, thereby revolving the air inducing and measuring drum 0. As the gas-drum B is revolved gas flows in through one of the narrow inlet-openings to, thereby gradually filling the screw-compartment between the adjacent vanes, as l and 2. Gas continues to flow into said compartment until the inlet-opening passes down into the liquid seal. The gas-pressure now continuing on the driving-shoulders of the successive or following screw-vane, which has been rising out of the liquid seal, continues the revolution of the drum, causing the outlet-opening 7 of the compartment which has just been filled with gas to rise above the sealing liquid and permit the free discharge of gas from said compartment at the discharge end of the drum. In the above-described operation gas is discharged at the outlet end of the drum under the same pressure and velocity as the air from the sister chamber or measuringcompartment of the air-drum and both are intimately mixed in chamber D. This operation of filling the compartments with gas, sealing the inlets thereof, and unsealing the outlets thereof in successive order is continued so long as gas is admitted to the drum, and the. mixture of gas and air is drawn off from chamber D.

The compartments, as indicated in Fig. 4, are so arranged that two of them are filling up with gas and two are discharging and one is idle at every position of the revolving drum,

- giving a balanced resistance at the discharging end.

The air-drum being attached to the same shaft as the gas-drum and revolving with the latter will take in air to the screw measuring-compartm cuts and deliver it into the mix ing-chamber D in practically the same manner as described with reference to the operation of the gasdrum B. As soon as any one screw compa'rtment of the air-drum is sealed at its receiving end it commences to discharge under pressure at the delivery end.

Under the construction and operation of the drums above described the gas and air are brought together under the same pressure and velocity in positively-measured proportions and a homogeneous mixture-of gas and air under pressure is delivered to the burners. By halving a perfectly-homogeneous mixture complete combustion takes place at IOS once-at the burner and all the carbonaceous" matter is consumed at a hightemperature, eifecting great economy in the use ofgasi claim as new, and desire to secure by Letters Patent, is- I 1'. 'In a-mixingameter, the propelling-drum constructed with screw-vanes, each having one or more driving-shoulders at the receiving end of the drum, outside of them'e'asurrug-compartments for causing the revolution saidshoulders, and means for supplying gas, substantially as described.

2-. Ina mixing-meter the propelling-'dru m having screw-vanes provided each with one" or more exterior driving-shoulders at the receiving end of 'thedrum, and an interior drivingshonlder in the interior of the measuring-compartments for causing revolution of the drum ders and means for supplying tially as described.

' 3. Ina mixing-meter adrum constructed'of; screw vanes, forming screwmeasuringrcompartments having comparativelynarrow openings at the inlet end of the drum, of

gas, substangradually-increasing width in cross-section and comparatively-wide openings at the dis charge end of the drum for decreasing the resistance to the revolution of the drum and facilitating t-hefiowor passage of both gas or aeriform fluid an'dthe' sealing liquid through the measuring-=compartments, substantially as described.

4. A meter-drum divided by helical vanes into screw measuring-compartments having narrow inlets at the receiving end of the drum and wide outlets at the discharge end for de creasing the resistance and facilitatingthe revolution of the drum, substantially as described.

5. A gas and air mixing meter comprising a propelling gas-drum and an induction airdrum mounted on the same shaft, said gasdrum having vanes, provided, each with a driving-shoulder at the receiving end of the drum, and means for supplying gas to bear against said shoulders whereby said drum and 1 the air-drum are more readily revolved by i pressure ofgas being metered, substantially as described. I

Having described. my invention, whatI F 6. A gas and air mixing meter comprising l:a propelling-drum constructed with vanes, one or more ofwhich has an exterior driving- ;shonlder at the receiving end, and an airmeasuring drum having narrow'inlets at the receiving end and wide outlets at the discharge end, both drums being niounted on the 1 same shaft, substantially as described.

of the drumby the pressure of gas against 7. In a mixing meter the gas-drum conistructed with a cylindrical shell, a shaft, a 1gas-receivingchamberas-e,spiralscrew-vanes between said receiving-chamber and the dis- .charge end of the drum, said vanes having Eeach', one or more driving-shoulders in the receiving-chamber, and means for supplying gas .to"the latter chamberto bear against said shoulders, substantially as described.

by the pressure of the gas against saidshoulf.

8; Ina mixing-meterthe gas-drum constructed'with a cylindrical shelland a gas-recei vingchamber ona shaft, a gas-supply pipe therefor, spiral vanes forming screw measuring-compartments between said receivingchamber and the discharge end of the drum, said vaneshaving, each, one or more'radial driving-shoulders in' the receiving-chamber for revolving the drum by the pressure of gas, against said shoulders, substantially as, described. I

9. A gas'and air mixing meter comprising a propelling gas-drum and an air-measuring drummounted on the same'shaft and each having a receiving-chamber, provided re spectively with a gas and an air inlet, said gas-drum having vanes provided each, at the receiving end of the drum, with a drivingshoulder, and said air-drum having smooth spiral vanes forming screw measuring-compartments between them, substantially as dcscribed.

In testimony whereof Iaifix my signature in presence of two witnesses.

GEORGE R. COTTRELL.

Witnesses:

E. B. CLARK, HARRY HQHOLLANDER. 

